Newly recruited park ranger Kang Hyeon-jo is sent to search for a teen who has gone missing in Jirisan National Park, but is impeded by a typhoon.

While pursuing a vision on the mountain, Hyeon-jo meets a man who's searching for his father’s ashes. The two continue their risky ascent together.

The rangers stop a shamanic ceremony and a girl passes a mysterious message to Hyeon-jo. The team gets a report that an elderly woman has disappeared.

Seo I-gang beholds a spooky scene in a video recording. Back in 2018, the team is unfairly blamed for the death of a villager.

I-gang tells Hyeon-jo that she saw someone with scratch marks on their hand. He suspects it may be the bomber. The rangers look for Lee Yang-seon.

Snow closes the park. I-gang learns that someone with the same name as her first love is coming to collect an item. A suspicious car approaches.

Following a rescue attempt, Hyeon-jo finds out that someone has been trying to kill him and realizes that the recent murders weren't a coincidence.

Lee Da-won is missing. The rangers go in search and find Da-won’s phone, which contains a suspicious voice recording with an unexpected person.

The police find a man lying in shock in the road. I-gang and Hyeon-jo get lost on their way to a village and see ominous lights in the darkness.

Cho Dae-jin is arrested as a suspect in Da-won’s death. I-gang develops a strong hunch that one of the rangers is actually the killer.

The rangers search for groups of climbers trapped in the park by heavy rainfall. I-gang meets a survivor of the 1995 flood that killed her parents.

The rainfall causes fatalities. Hyeon-jo discovers that the accident on the bridge was intentional and looks into the connections between the victims.

At Geomeundarigol Village Hyeon-jo catches a suspicious man in black gloves. After hearing his testimony, Hyeon-jo starts to suspect someone new.

Hyeon-jo’s family decides to switch off his life support. The rangers start looking into people connected to the village, and I-gang has a revelation.

After the truth is finally revealed, I-gang grills the perpetrator. The culprit goes to conceal some evidence, but there meets Hyeon-jo’s soul.